The AN-5-203 is a half-wave, phase-controlled thyristor (SCR) type AVR. It is designed to regulate the output voltage of brushless generators ranging from 5kW to 15kW. Unlike electronic modules that use transistors, the SCR design makes this AVR robust against voltage spikes and over-current conditions, though it does have specific wiring nuances that must be followed exactly.
Direct DC output to the generator's exciter field windings. F+ (Red): Positive terminal. F- (White/Black): Negative terminal. Technical Specifications Specification Input Voltage Range 140V – 300V AC Output Voltage 220V ±1.5% Power Capacity Correction Speed ~1 second for minor deviations Protections Under-speed, sensing loss, and over-excitation Installation and Adjustment Guide Universal - GenPowerUSA
Use shielded wires for potentiometer connections to avoid EMI (Electromagnetic Interference). Check Polarity: Double-check F+ and F- connections. Initial Setup/Calibration:
⚠️ Never attempt to alter wiring on a live generator. Ensure the prime mover is completely shut off, and the battery lines are disconnected before exposing the control panel. an-5-203 avr wiring diagram pdf
Commonly found in DCA-13ESK, 15ESK, 25SPK, 25ESK, 25ESI, and 25SPI.
Use a flathead precision screwdriver to turn the screw. Turn clockwise to increase voltage; turn counter-clockwise to decrease voltage.
Understanding the nominal input and output thresholds of the AN-5-203 AVR ensures it operates safely within your system's design limits without damaging downstream hardware. Specifications & Operating Limits 400 VAC, 50 Hz / 60 Hz Auxiliary Winding Input AC 55V – 220V Maximum Excitation Output 120 VDC / 5 ADC continuous (for up to 10 seconds) Generator Field Resistance ≥is greater than or equal to Ωcap omega Steady-State Regulation Rate Voltage Adjustment Range ≥is greater than or equal to Minimum Residual Voltage ≥is greater than or equal to 5V at 30 Hz (for positive voltage build-up) 2. Core Terminal Connections and Wiring Diagram Description Direct DC output to the generator's exciter field windings
If the voltage "hunts" (bounces up and down), adjust this screw until the needle or digital display stays steady.
Disclaimer: Working with electrical generators can be dangerous. Ensure proper safety procedures are followed. If you are not qualified, please contact a professional generator technician.
Identify the output phases of the generator that match the voltage rating of your AVR sensing circuit (e.g., 220V or 400V). If you are not qualified
Although the exact OEM wiring diagram isn't freely available, the AN-5-203 follows a . Based on technical descriptions and field experience, here is the standard terminal assignment:
Set the idle voltage to roughly 230V for a 220V system, or 115V for a 110V system under no-load conditions. Troubleshooting Common AVR Wiring Issues
What you are experiencing (low voltage, hunting, etc.) If you are using a 50Hz or 60Hz system I can give you customized steps to fix the issue. Share public link